QuickBooks OnlineConnect multiple QuickBooks Online companies to Claude
An MCP connection to QuickBooks Online carries one company. If you keep the books for several companies, one connection is not enough. Switching means authorizing again, and the previous company is gone until you switch back. Handling several accounts of the same connector is an open request on GitHub (anthropics/claude-code #27302).
This guide uses ProxyLoom to put several QuickBooks Online companys behind a single MCP connection, so Claude can work in any of them and you say which one by name. It takes about five minutes, with no app registration and no JSON config.
What you end up with
One connector in Claude called ProxyLoom. Behind it, each QuickBooks Online company you connected, with a label you chose (for example acme, client-a, client-b). Every QuickBooks Online tool Claude sees carries an account argument, so "list the overdue invoices in client-a" and "run this quarter's P&L for acme" both work in the same conversation, without disconnecting anything.
1. Sign up for ProxyLoom
Create an account at https://app.proxyloom.dev/sign-up.
2. Connect each QuickBooks Online company
Signing in puts you on the Connections screen. Click + Connect an account, pick QuickBooks Online, and click Authenticate and connect →. QuickBooks Online's own consent screen opens; approve the access. Repeat for each company you want. Each one becomes a separate connection with its own token.
Back on the Connections screen, give each connection a label: click Add a label in that connection's Label column. The label is the name you will use when you talk to Claude, so use what you already call it:
acme,client-a,client-b. Without a label ProxyLoom falls back to the name QuickBooks Online reports for the connected account.3. Add ProxyLoom to Claude
In Claude, open Settings → Connectors and click Add (top right). The Add custom connector dialog opens: give it a name — ProxyLoom — paste your ProxyLoom URL as the MCP server URL, and continue. The URL sits in the MCP Endpoint bar at the top of ProxyLoom's Connections screen, with a copy button next to it.
Continuing opens ProxyLoom's authorization in your browser: sign in once and approve, and the connector is authorized. That is the only connection Claude holds.
This works the same in the Claude desktop app, claude.ai and Claude Code. Any client that speaks Streamable HTTP MCP and OAuth 2.1 (Codex, Cursor, ChatGPT) is set up much the same way, with the same URL.
4. Use it
Ask Claude to list the connected accounts to confirm everything is there:
Which QuickBooks companies do you have?
Claude asks ProxyLoom and answers with the labels. From then on, name the company in the request:
List the overdue invoices in client-a, oldest first.
Run this quarter's profit and loss for acme and tell me what moved.
If a request is ambiguous, Claude asks which company you mean rather than guessing. Which account was used is recorded in ProxyLoom's audit log, so you can check afterwards.
Notes
- There is nothing to set up on the QuickBooks Online side. Each connection carries only what you approved on QuickBooks Online's consent screen: querying, creating, updating, deleting and voiding records — invoices, bills, customers, vendors, accounts, journal entries and payments — running reports, sending and downloading sales-form PDFs, and reading and writing attachments. You can revoke that grant at any time — delete the connection on ProxyLoom's Connections screen, or remove ProxyLoom in the connected apps of your Intuit account.
- Adding a company later does not mean repeating step 3, Add ProxyLoom to Claude — that one is done once and never again. Connect it on ProxyLoom's Connections screen, and Claude sees it from then on.